DUAL ENZYME LABELS FOR SIMULTANEOUS HETEROGENEOUS ENZYME-LINKED COMPETITIVE-BINDING ASSAYS

The use of two enzyme labels in a dual analyte simultaneous heterogene ous enzyme-linked competitive binding assay is examined. Reaction cond itions for monitoring glucose-6-phosphate dehydrogenase (G6PDH) and be ta-galactosidase (beta-gal) activities are found which enable the inde pendent measurement of each enzyme activity in the presence of the oth er. The two enzymes are used as labels in the development of a model s imultaneous heterogeneous competitive binding assay for detecting the biotin and vitamin B-12 content of vitamin tablets. The simultaneous a ssay is shown to exhibit analytical dose-response characteristics comp arable to those of the single analyte assays. The potential use of the G6PDH/beta-gal enzyme pair for devising other dual analyte competitiv e and non-competitive binding assays is discussed.